1. Field of the Invention
The present invention relates to mats used for erosion control, pipeline protection, crossings, and many other subsea uses, and methods of installing such mats. More particularly, the present invention relates to an improved mat and method of manufacture wherein a specially configured mould provides concave and convex sides, the concave side providing a plurality of inclined surfaces, each having one or more anchors and wherein the convex side provides hemispherically shaped projections which extend over a bottom surface of the mould, the mould being configured to accept a cementitious fill for forming an block and wherein the blocks can be connected with cables or ropes to form a mat.
2. General Background of the Invention
Erosion control mats have been used for many years to protect soil surfaces such as the banks of water bodies (lakes, rivers, etc.).
Another example of an erosion control mat is the Pilaar (U.S. Pat. No. 3,597,928). The Pilaar patent relates to an erosion controlling protective surface for a soil mass. The device includes a flexible supporting sheet that can conform to the contour of the soil and blocks that are mounted on the supporting sheet. The mat provides drainage passageways therethrough so that water can pass through the surfacing. Preferably, the surfacing includes a filter and the blocks are secured with the supporting sheet.
The Nelson (U.S. Pat. No. 3,386,252) shows a rip rap structure that employs concrete blocks connected together.
Cables are employed to hold blocks together in the Landry (U.S. Pat. No. 4,227,829) to form a matrix.
The Crow (U.S. Pat. No. 4,375,928) shows rows of blocks held together by a continuous wire cable which is embedded in each block.
The Waters (U.S. Pat. No. 4,683,156) shows an erosion control blanket of segments. The segments are said to be of concrete placed into shells. The segments are held together with a rope network. Openings in the shells provide points of entry for the ropes.
The Rudloff (U.S. Pat. No. 5,484,230) provides a concrete block revetment system for soil erosion prevention. The system of the Rudloff patent provides concrete blocks that are cable interconnected to form a matrix. The matrix of blocks overlies and holds in place a layer of permeable geotextile overlying a protected soil area.
The Angel (U.S. Pat. No. 6,027,285) entitled “Mat Installation” shows cable connected erosion control blocks that can be used over pipe lines. Other patents issued to Angel include U.S. Pat. Nos. 5,722,795; 5,846,023; and 5,944,449.
The Landry (U.S. Pat. No. 4,486,120) provides a spreader bar for the installation of soil erosion prevention mats.
The Daniel (U.S. Pat. No. 6,406,217) provides a lifting and placing device for seabed mats.
Other patents possibly relevant to the construction and use of mats for erosion control, pipeline protection, crossings, and many other subsea uses can be seen in the following table, the listing being chronological and otherwise of no significance. Each of the patents listed in the table is hereby incorporated herein by reference.
The following US Patents are incorporated herein by reference:
Issue DatePat. No.TitleMM/DD/YYYY3,386,252Rip Rap Structure DeviceSep. 08, 19663,597,928Erosion ControlAug. 10, 19714,227,829Soil Erosion Preventing BlocksOct. 14, 19804,375,928Flexible Concrete For Soil ErosionMar. 08, 1983Prevention4,486,120Spreader Bar For Soil ErosionDec. 04, 1984Prevention Mats4,683,156Flexible BlanketJul. 28, 19875,484,230Concrete Block Revetment SystemJan. 16, 1996For Soil Erosion Prevention5,722,795Non-Abrasive Subsea MatMar. 03, 19985,846,023Non-Abrasive Subsea MatDec. 08, 19985,944,449Non-Abrasive Subsea MatAug. 31, 19996,027,285Mat InstallationFeb. 22, 20006,406,217Lifting and Placing Device forJun. 18, 2002Seabed Mats